Abstract

Hydrogenated amorphous silicon (a-Si:H) thin-film transistors (TFTs) are widely used in many areas and the most important application is in active matrix liquid crystal display. However, the instability of the a-Si:H TFTs constrains their usability. These TFTs have been annealed at higher temperatures in hope of improving their electrical performance. But, higher anneal temperatures become a constraint when the TFTs are grown on polymer-based flexible substrates. This study investigates the effect of anneal time on the performance of the a-Si:H TFTs on PEN. Thin-film transistors are annealed at different anneal times (4 h, 24 h, and 48 h) and were stressed under different bias conditions. Sub-threshold slope and the off-current improved with anneal time. Off-current was reduced by two orders of magnitude for 48 hours annealed TFT and sub-threshold slope became steeper with longer annealing. At positive gate-bias stress (20 V), threshold voltage shift (ΔVt) values are positive and exhibit a power-law time dependence. High temperature measurements indicate that longer annealed TFTs show improved performance and stability compared to unannealed TFTs. This improvement is due to reduction of interface trap density and good a-Si:H/insulator interface quality with anneal time.

Original languageEnglish (US)
Title of host publicationAmorphous and Polycrystalline Thin-Film Silicon Science and Technology - 2010
Pages403-408
Number of pages6
StatePublished - Dec 24 2010
Event2010 MRS Spring Meeting - San Francisco, CA, United States
Duration: Apr 5 2010Apr 9 2010

Publication series

NameMaterials Research Society Symposium Proceedings
Volume1245
ISSN (Print)0272-9172

Other

Other2010 MRS Spring Meeting
CountryUnited States
CitySan Francisco, CA
Period4/5/104/9/10

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ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Indluru, A., Venugopal, S. M., Allee, D., & Alford, T. (2010). Threshold voltage shift variation of a-Si:H TFTs with anneal time. In Amorphous and Polycrystalline Thin-Film Silicon Science and Technology - 2010 (pp. 403-408). (Materials Research Society Symposium Proceedings; Vol. 1245).